Leuco sulphuric acid esters of vat dyestuffs of the anthanthrone series



iii

Patented Oct. 22, 1940 ,DYESTUFFS OF THE ANTHANTHRONE';

' SERIES I Werner Zerweck and Josef Riedmair, Frankfort- Y on-the Main-Fechenheim, Germany, assignors.

to General'Aniline' & Film Corporation, New; York, N."Y., a corporation of Delaware 7 Nameles- Ap plication December 7, 1939, SerialNo. 307,938. 111 Germany December 10, 1938- 1 claims. (01. 260-359) Our present invention relates to leuco sulphuric acid esters of vat dyestuffs of the anthanthrone series, more particularly to those of the general formula, O.SOa.alk ali .SO3.alkali I wherein R stands for a member of the group consisting of alkyl radicles and radiclesof the benzene series. They'arelobtained by reducing and esterifying in the presence of tertiary bases with sulphur trioxide or compounds setting free sulphur trioxide the 2.7-dialkoxyanthanthrone as described in U. S. Patentsgl,805,912 and 1,805,913, or the corresponding diaryloxyanthanthrones.

The leuco sulphuric ester salts thus obtained are very stable and water, soluble. They surpass the dye'stufisYthemselves-as regards tinctorial power and are particularly suitable for cotton printing processes. l" In. order to further. illustrate our invention the.

, following examples arelgiven, the parts being by weight and all temperatures in degrees centigrade.

' Example 1 To 200 parts of pyridine, while cooling, slowly 52 parts of chlorsulphonic acid and thereupon a mixture of 20 parts of finely powdered 2,7-dimethoxyanthanthrone and 20 parts of iron powder are added. The mixture is maintained at about 55 for about 5 hours. When no more reddish violet vat dyestuff is present the yellowish reaction pulp is pour-ed into a solution of parts of caustic potash in 2000 parts of water. Then the mixture is heated to about 60 and the iron residue is removed by filtration. From the filtrate by adding potassium chloride the potassium salt of the leuco sulphuric acid ester of the formula may be isolated and is dried invacuo. Itis: a;

yellow easily water-solublefpowderandyields according vto the usual methods strong reddish violet prints of excellent fastness on cottonand other fibres. I

In contradistinction thereto thedyestufi itself;

is less suitable for printing cotton, since only feeble and dull shades areobtainable therewith. v

When starting for the above described process for instance, from 2.7-di-isopropylo xyanthanthrone or 2.7-.di-(3 ch1oropheny1oxy) -anthanthrone which both are themselves not suitable as vat dyestuffs likewise leuco sulphuric ,acid esters are obtained yielding oncotton and other fibres strong reddish violet prints-ofa good fast ness, particularly to light. The 2.7-di-(3'- chlorophenyloxy)-anthanthrone not described hitherto in literature may be prepared for instance by converting the 5- chloro-8-nitronaphthalene-l-carboxylic acid by decomposition with 3-chlorophenolinto the 5-(3-chlorophenyloxy) 8 nitr'onaphthalene 1 carboxylic acid, reducing toth'e corresponding amino compound and carrying out the formation of the corresponding dinaphthyl compound and the closure of the anthanthrone'ring in the known manner. 'I'he-leuc sulphuric acid ester corresponds to the formula 0 .so aK Example 2 pyridinium salt of the formed leucosulphuric acid ester separates It is isolated and by digesting with a mixture of parts of a caustic soda solution of 40 B. and about 5000 parts of water at about 60 B. it is transformed into the water-soluble sodium salt. The solution is separated from the excess of copper and impurities by filtration in the heat and from the filtrate the sodium salt is separated by adding sodium chlorideand then it is isolated. It corresponds to the formula O.SOa.Na

It is when dry alight yellow powder and yields according to the known methods on cotton and other fibres bright purple-red dyeings and prints (|).S Oaalkali wherein It stands for a member of the group consisting of alkyl and radicles of the benzene series.

2. The vat dyestufi leuco sulphuric acid ester of the formula 0.SO:.K

HzOO

OCH:

.SOa.K

which is a yellow easily watersoluble powder and yields according to the usual methods strong reddish violet prints of excellent fastness on cot- 15 ton and other fibres.

3. The vat dyestufi leuco sulphuric acid ester of the formula 25 .SO:.K

I which is a yellow easily watersoluble powder and yields according to the usual methods strong reddish violet prints of excellent fastness on setton and other fibres.

4. The vat dyestuff leuco sulphuric acid ester of the formula 0.SOa.N8

H o o 002K; 8 some which is a light yellow powder and yields according to the usual methods bright purple-red dyeings and prints of excellent fastness on cotton and other fibres. W

WERNER ZERWECK. JOSEF RIEDMAIR. 

